Enhancement of dielectric and ferroelectric properties by addition of Pt particles to a lead zirconate titanate matrix

Ferroelectric/metal composites have been characterized for their electric f ield dependence of the dielectric and ferroelectric properties. The composi tes show an interesting change of dielectric properties with increasing met al concentration. A relatively high dielectric constant, up to four times a s high as that of monolithic lead zirconate titanate (PZT), is observed in the investigated composition range. The dielectric properties are clearly e lectric field dependent. The tunability of the composite, defined as the di fference between the dielectric constant with no applied voltage and the di electric constant with an applied voltage, divided by the dielectric consta nt with no applied voltage, was found to be similar to 17, whilst for the m onolithic PZT ceramics it is about 3 only. This offers perspectives for app lication of these composites in lighting electronics and voltage controller s. Ferroelectric hysteresis measurements on these composites revealed a squ are-shaped hysteresis loop with remnant polarization comparable with single PZT ceramics, while the coercive field was much lower than that of pure PZ T ceramics. This might be interesting for application of these composites a s a ferroelectric memory material with decreased switching voltage. (C) 200 0 American Institute of Physics. [S0003-6951(00)02046-5].